Bursaphelenchus xylophilus is a pine wilt disease pathogen that causes the most serious damage to forests in Japan. Bursaphelenchus xylophilus is an invasive species from North America that has caused dramatic damage to Japanese pines, which lacked resistance to Bursaphelenchus xylophilus. Currently, except for Hokkaido and Aomori prefectures, Bursaphelenchus xylophilus has spread throughout Japan.
To diagnose pine wilt disease, it is necessary to detect Bursaphelenchus xylophilus from a piece of wood taken from a dead pine tree. Conventionally, this is usually carried out by isolating Bursaphelenchus xylophilus from the piece of wood using the Baermann method and performing a morphological observation. The Baermann method (for example, refer to Non-Patent Document 1) is a method in which a specimen is wrapped in tissue paper and dipped in a funnel filled with water. If a nematode is in the specimen, the nematode will fall to the bottom of the funnel. The morphology of the fallen nematode can then be confirmed with a microscope to determine whether it is Bursaphelenchus xylophilus or not.
However, in addition to requiring a very long time for the isolation of the nematode from the piece of wood, the Baermann method requires specialist knowledge concerning nematode morphology. Furthermore, expensive equipment such as a microscope is necessary for detection of the nematode. Therefore, detection of Bursaphelenchus xylophilus has until now been carried out at specialist institutions having the people and equipment capable of distinguishing nematodes. In other words, an easy method for detecting Bursaphelenchus xylophilus has not existed until now.    [Non-Patent Document 1] Masahara Mamiya, Kazuyoshi Futai, Hajime Kosaka, Natsumi Kanzaki (2004), Wood Nematodes (Nematode Experiment Methods, edited by the Japanese Nematological Society, Japanese Nematological Society, Ibaraki) 134-153.